No.l.] GRAY AND HOOKER ON THE ROCKY MOUNTAIN FLORA. 15 



which it abounds at the elevation of 7,500 or 8,000 feet, or rather once 

 abounded, for, as Professor Sargent states, the trees within reach are 

 fast being cut away to supply the mines with timbering. For this pur- 

 pose its strong and close-grained, tough, and reddish wood is preferred 

 to that of any other available tree. 



Pinus tnonophylla, the single-leaved Nut Pine, is a most characteristic 

 tree of the interior basin, mainly of the western and southern jiart of it, 

 which it only slightly overpasses in Arizona and Southeastern Califor- 

 nia. It is a tree of slow growth, and of only ten to twenty feet in height, 

 yet with trunk sometimes two feet in diameter, and with white and soft 

 resinous wood, furnishing valuable fuel, and in this region of narrow 

 choice it is much used for making charcoal. The great importance of 

 the tree was, and still is, in the crop of large and delicately flavored 

 seeds which it yields, constituting a staple article of food for the Indians 

 of the Great Basin. 



Pinus edulis, the Pinon or Nut Pine of the Southeastern Eocky 

 Mountains, extends from the Arkansas to New Mexico and Arizona, a 

 tree not larger than the foregoing, also has its importance in its edible 

 seeds, and in the value of its wood for fuel. 



Pimis Jlexilis, the White Pine of the Eocky Mountains, and belonging 

 to the same general section as the Atlantic White Pine, but peculiar in 

 its thick cones and good-sized edible seed, inhabits the higher region of 

 the Eocky Mountains from Montana to New Mexico and the higher 

 Nevada ranges. What is considered as a short-coned variety of it [albi- 

 caulis) is the highest tree, commonly reduced to a shrub, on and around 

 alpine summits of the Sierra Nevada throughout all its length, and even 

 northward in the Cascade Eanges to latitude 53°, in British Columbia. 

 In the Eocky Mountain region this tree becomes large enough to be 

 sawn into boards ; and its light and soft wood is the best substitute for 

 the Eastern white-pine lumber. 



Pseudotsuga Douglasii, the Douglas Spruce, the most valuable timber 

 tree of the west coast (with the possible exception of the Eedwood), is 

 hardly one of the second rank in such of the interior districts as it in- 

 habits. But it is apparantly absent from all the ranges west of the 

 Uintas and south of the forty-second parallel until the western slope of 

 the Sierra Nevada is reached, and is not very abundant in those of Col- 

 orado and New Mexico. It extends along the northern Eocky Mount- 

 ains almost to latitude 54°, and a stunted variety descends on its east- 

 ern flanks. It is found S(;attered among other Coniferiie at middle ele- 

 vations. But from Oregon to British Columbia, toward the coast and 

 in the river valleys, this noble tree forms entire and vast forests, and 

 takes a development in size and in numbers which is truly extraordi- 

 nary. A large-fruited variety [inacrocmya) occurs at the southern ex- 

 tremity of the Sierra Nevada at no great elevation, and extends even 

 into Mexico. 



Picea Engelnmnni {Abies JEngelmanni of Parry, the discoverer), the 



